Extender question

[siejones]

Ok so we all know that in general a lens does not perform at it's best wide open but if you use an extendor lens that takes you widest aperture up but one stop does the same rule apply.

Example: Say a 70-200 F4 lens would perform better at F5.6 than at F4.0 but with a 1.4 extender it's widest is F5.6 so does that mean that now because F5.6 is now the widest aperute the lens is at it's worst until F8?

Hpoe you see what I am getting at.

 

[CT]

Ok so we all know that in general a lens does not perform at it's best wide open but if you use an extendor lens that takes you widest aperture up but one stop does the same rule apply.

Example: Say a 70-200 F4 lens would perform better at F5.6 than at F4.0 but with a 1.4 extender it's widest is F5.6 so does that mean that now because F5.6 is now the widest aperute the lens is at it's worst until F8?

Hpoe you see what I am getting at.

Generally speaking... Yes to all of that.

I have to say though that only a few years ago extenders weren't really recommended with prime lenses, and were pretty well a guaranteed nono with a zoom lens, but I've been amazed at the image quality I've obtained with the 1.4X converter with the 100-400L the 180L macro and the 500L as well as some of the results I've seen from others, so the technology in these converters has obviously come on in leaps and bounds.

Most of the time with the 500L and with the bad light at this time of year I've been forced to use the lens wide open with the converter anyway and it's often difficult to see any drop in quality at all.

So in short I think you have to suck it and see really unless you're sticking a converter behind a lens which is a known poor performer when in all probability you'll be disappointed.

 

[siejones]

Generally speaking... Yes to all of that.

I have to say though that only a few years ago extenders weren't really recommended with prime lenses, and were pretty well a guaranteed nono with a zoom lens, but I've been amazed at the image quality I've obtained with the 1.4X converter with the 100-400L the 180L macro and the 500L as well as some of the results I've seen from others, so the technology in these converters has obviously come on in leaps and bounds.

Most of the time with the 500L and with the bad light at this time of year I've been forced to use the lens wide open with the converter anyway and it's often difficult to see any drop in quality at all.

So in short I think you have to suck it and see really unless you're sticking a converter behind a lens which is a known poor performer when in all probability you'll be disappointed.

Thanks CT

I want to get an extender but I don't like the idea that at F5.6 the 70-200 F4 is no longer as good as it was without the extender (regardless of the extenders degredation)